System of distribution



June 18, 192 9.

Phase I D. C. PRINCE SYSTEM OF DISTRIBUTION Filed Sept. 20, 1923 PhaseZ Irv/enter I David C. Prince,

His Attorney.

Patented June 18, 1929.

UNITED STATES PATENT OFFICE.

DAVID C. PRINCE, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SYSTEM OF DISTRIBUTION.

Application filed September 20, 1923.

My present invention relates to systems of electrical distribution employing apparatus of the thermionic type, and more particularly to means for supplying heating current to the cathodes of such devices.

In the operation of a thermionic electron discharge device which is designed to carry large currents, one disadvantage is met with in the fact that the magnetic field produced by the current required to heat the cathode to incandescence tends to prevent the escape of electrons from the cathode. As a result, part of the voltage applied to the device to carry the electrons over to the anode must be employed to overcome this tendency and the efiiciency of operation of the device is reduced.

The object of my invention is to overcome this disadvantage in cases where a device is required to carry current only a portion of the time during which the system in which it is employed is in operation.

In carrying my invention into effect I provide means for automatically reducing the heating current supplied to the cathode during the periods when the device is carrying current and permitting the heating current to reach its maximum value required for heating the cathode during the periods when the device is not required to carry current.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation will best be understood by reference to the following description taken in connection with the accompanying drawing in which Fig. 1 shows diagrammatically a system of circuit connections whereby my invention may be carried into effect, and Fig. 2 represents the voltage relations of different portions of the system.

I have indicated in Fig. 1 a system employing four thermionic rectifiers 1, 2, 3 and 4, for rectifying current from a two-phase alternating supply system comprising supply conductors5, 6 for one phase and 7, 8 for the second phase, and supplying the rectified current to the conductors 9, 10 of a direct current distribution system. The anodes of rectifiers 1 and 2 are connected to opposite terminals of the secondary 11 of a transformer the primary 12 of which is supplied Serial No. 663,930.

with current from the first phase of the alternatlng current supply system, and the anodes of rectifiers 3 and 4 are connected to opposite terminals of the secondary 13 of a transformer, the primary 14 of which is supplied with current from the second phase of the alternating current supply systems.

Heating current for the cathodes of rectifiers 1 and 2 is supplied by transformers 15 and 16 the primary windings 17 and 18 of which are connected in series across the second phase. Similarly the cathodes of rectifiers 3 and 4 are supplied with heating current by transformers 19 and 20, the primary windings '21 and 22 of which are connected in series across the first phase of the alternating current supply system. Direct current distribution conductor 9 is connected to the mid-points of secondaries 11 and 13 and direct current distribution conductor 10 is connected to the mid-points of the secondaries 23 of transformers 15, 16, 19 and 20.

Transformers 15, 16, 19 and are provided with additional windings 24, 25, 26 and 27 which are supplied with direct current from the supply conductors 28 and 29.

The windings supplied with direct current are so arranged as to produce saturation in opposite directions in the two transformers 15 and 16 and in the two transformers 19 and 20.

The voltages induced in the different transformers are indicated by the curves of Fig. 2. If A represents the voltage impressed from phase 2 upon transformers 15 and 16 the voltage will be divided between the two transformers and on account of the saturation produced by the direct current flowing in windings 24 and the voltage will be unequally divided between the two transformers. Curve B may represent the voltage of transformer 15 and curve C may represent the voltage of transformer 16. If curve D represents the positive voltage applied to the anode of rectifier 1 from phase 1 it is apparent that little or no current will be supplied to the cathode of rectifier 1 while rectifier 1 is in operation. Therefore, no magnetic field will be produced to oppose the flow of electrons to the anode. Similarly when the anode of rectifier 2 becomes positive the voltage applied to the secondary of transformer 16 will be substantially zero and when rectifiers 3 and 4 are required to supply rectified current the heating current of their cathodes will be reduced to substantially zero.

The sum of voltages B and C may be made equal to voltage A so that only sine wave voltages appear in the supply circuit of the transformers. No current of the'fundamental frequency will flow in the direct current saturation windings because of the fact t at these windings are reversed. A second harmonic potential will be induced in the direct current windings but since the fundamental potentials set up in the two pair of windings are displaced by 90 the second harmonics ,will be displaced by 180 and no current of the second harmonic will flow in the saturation windings.

While I have shown and described only one modification of my invention it is apparent that many modifications in the circuit arrangements for supplying the different operating currents to the electron discharge devices as well as in the particular functions served by such devices may be made Without departing from the scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure .by Letters Patentof the United States, is

1. The combination with an electron discharge device which is connected in a circuit arrangement in which it is required to carry current only during intermittent periods of time of a transformer for supplying heating current to the cathode of said device, and means operable independently of the load current of said device for controlling the degree of saturation of the core of said transformer and thereby reducing the value of the heating current supplied to the cathode during the periods when the device is required to carry current.

2. The combination with an electron discharge device which is connected in a circuit arrangement in which it is required to carry current only during intermittent periods of time of a transformer for supplying heating current to the cathode of said device, and means operable independently of the load current of said device for supplying a direct current to a winding of said transformer for controlling the degree of saturation of the core of said transformer and thereby reducing the value of the heating current supplied.

to the cathode during the periods when the device is required to carry current. 3. The combination in an electrical distribution system of a plurality of thermionic discharge devices which are so connected to the system and operated that each device iS' required to carry current only during short intermittent periods of time, potential trans formers for supplying heating current to the cathode of each device, and a circuit connected to said potential transformers for controlling the supply of current to the cathodes,

and automatically reducing the value of the heating current supplied to each cathode during the periods when its device' is carrying current. I

4. The combination in an electrical distribution system of a plurality of thermionic discharge devices which are so connected to the system and operated that each device is required to carry'current only during short 7 intermittent periods of time, individual transformers for supplying alternating heating current to the cathode of each device, and means operable independently of the load current of said device for controlling the de gree of saturation of the core of each transformer and thereby reducing the value of the heating current supplied to each cathode during the periods when its device is carrying current.

5. The combination in an electrical distri? bution system of a plurality of thermionic discharge devices, an alternating current source of supply for said devices which is so connected thereto that each device will carry current only during short intermittent periods of time, potential transformers for sup- 90 plying heating current to the cathodes of said devices and means operable independeiitly of the load current of said device for automatically reducing the value of the heating current supplied to each cathode during the periods when its device is carrying current.

6. The combination in an electrical distribution system of a plurality of thermionic discharge devices. an alternating current source of supply for said devices which is so connected theretolthat each device will carry current only during short intermittent periods of time, means for supplying'heatmg current to the cathodes of said devices from 1 said alternating current source, and means operable independently of the magnitude of the load current transmitted through said devices for automatically reducing the value of the heating current supplied to each cathode during the periods when its device is carrying current.

7. The combination in an electrical distribution system of a plurality of thermionic discharge devices, an alternating current source of supply for said devices which is so connected thereto that each device will carry current only during short intermittent periods of time, individual potential transformers for supplying heat-ing current to the cathode of each device which is displaced in phase from the current supplied for the opdischarge devices, an alternating current source of supply for said devices which is so connected thereto that each device will carry current only during short intermittent periods of time, individual potential transformers for supplying heating current to the cathode of each device which is displaced in phase from the current supplied for the operation of the device and means operable independently of the magnitude of the load current transmitted through said devices for automatically reducing the value of the heating current supplied to each cathode during the periods when its device is carrying current.

9. The combination in a rectifying system of a plurality of thermionic rectifiers connected to a polyphase alternating current supply system in such a way that each rectifier carries current only during short regular periods of time, transformers for supplying heating currents to the cathodes of said rectifiers and means for producing a saturation of the cores of said transformers in sucha way that the heating current supplied to each cathode will be reduced during the periods of time whenthe corresponding rectifier carries current.

10. The combination in a rectifying system of a plurality of thermionic rectifiers connected to a polyphase alternatingcurrent-supply system in such a way that each rectifier carries current only during short intermittent periods of time, individual transformers for supplying heating currents to the cathodes of said rectifiers and means for supplying a direct current to a winding of each transformer and thereby varying the saturation of the cores of the different transformers in such a way that the heating current supplied to each cathode will be reduced during the periods of time when the corresponding rectifier carries current. e

11. The combination in a rectifying system of a polyphase alternating current supply system, a pair of thermionic rectifiers oppositely connected to each phase of said supply system, means for supplying heatin current to the cathodes of each pair of recti ers from a phase of said supply system different from that to which the rectifiers are connected, said means comprising individual transformers for each rectifier, each of said transformers having a primary and a secondary winding, and a third winding which is supplied with direct current.

12. The combination in a rectifying system of a polyphase alternating current supply system, a pair of thermionic rectifiers oppositely connected to each phase of said supply system, means for supplying heating current to the cathodes of each pair of rectifiers from a phase of said suppl system'different from that to which the rectifiers are connected, said means comprising individual transformers for each rectifier, each of said transformers having a primary and a secondary winding, and a' third winding which is supplied with direct current, said third windings being so arranged with respect to the primary windings that the core of each transformer is saturated only during every alternate half cycle of the alternating potential supplied to the rectifier.

13. The combination in a rectifying system of a polyphase alternating current supply system, a pair of thermionic rectifiers oppo sitely connected to each phase of said supply system, means for supplying heating current to the cathodes of each pair of rectifiers from a phase of said supply system different from that to which the rectifiers are connected, said means comprising individual transformers for each rectifier, each of said transformers having a primary and a secondary winding, and a third winding which is supplied with direct current, said third windings being so arranged with respect to the primar windings as to produce a saturation of t e cores of said transformers which will cause the heating current supplied to each cathode to be reduced during the periods of time during which the potential of the corresponding anode is positive.

14. The combination in a rectifying system of a two phase alternating current supply system, a pair of thermionic rectifiers oppositely connected to each phase of saidsupply system, means for supplying" heating current to the cathodes of each pair of rectifiers from that phase of the alternating current supply to which the other pair is connected, said means comprising individual transformers for each rectifier, each of said transformers having a primary and a secondary winding, and a third winding which is supplied with direct current.

15. The combination in a rectifying system of a two-phase alternating current supply system, a pair of thermionic rectifiers oppositely connected to each phase'of said supply system, means for supplying heatin current to the cathodes of each pair of recti ers from that hase of the alternating current supply to w ich the other pair isconnected, said means comprising individual transformers for each rectifier, each of said transformers having a primar and a secondary winding, and a third win ing which is supplied with direct current, said third windings being so arranged with respect to the primary windings that the core of each transformer is saturated only during every alternate half cycle of the alternating potential supplied to the rectifier.

16. The combination in a rectifying system of a two-phase alternating current supply.

system, a pair of thermionic rectifiers 0ppositely connected to each phase of said supply system, means for supplying heating current to the cathodes of each pair of rectifiers from that phase of the alternating current supply to which the other pair is connected, said means comprising individual transformers for each rectifier, each of said transformers having a primary and a secondary Winding, and a third winding which is supplied With direct current, said third windings being so arranged with respect to the primary wind- 

